coffread.c

早期freebsd实现

     int nsyms;
     struct objfile *objfile;
{
  FILE *stream; 
  register struct coff_context_stack *new;
  struct coff_symbol coff_symbol;
  register struct coff_symbol *cs = &coff_symbol;
  static struct internal_syment main_sym;
  static union internal_auxent main_aux;
  struct coff_symbol fcn_cs_saved;
  static struct internal_syment fcn_sym_saved;
  static union internal_auxent fcn_aux_saved;
  struct symtab *s;
  
  /* A .file is open.  */
  int in_source_file = 0;
  int num_object_files = 0;
  int next_file_symnum = -1;

  /* Name of the current file.  */
  char *filestring = "";
  int depth = 0;
  int fcn_first_line = 0;
  int fcn_last_line = 0;
  int fcn_start_addr = 0;
  long fcn_line_ptr = 0;
  struct cleanup *old_chain;
  int val;

  stream = fopen (objfile->name, FOPEN_RB);
  if (!stream)
   perror_with_name(objfile->name);

  /* Position to read the symbol table. */
  val = fseek (stream, (long)symtab_offset, 0);
  if (val < 0)
    perror_with_name (objfile->name);

  /* These cleanups will be discarded below if we succeed.  */
  old_chain = make_cleanup (free_objfile, objfile);
  make_cleanup (fclose, stream);

  current_objfile = objfile;
  nlist_stream_global = stream;
  nlist_nsyms_global = nsyms;
  last_source_file = NULL;
  memset (opaque_type_chain, 0, sizeof opaque_type_chain);

  if (type_vector)			/* Get rid of previous one */
    free ((PTR)type_vector);
  type_vector_length = 160;
  type_vector = (struct type **)
		xmalloc (type_vector_length * sizeof (struct type *));
  memset (type_vector, 0, type_vector_length * sizeof (struct type *));

  coff_start_symtab ();

  symnum = 0;
  while (symnum < nsyms)
    {
      QUIT;			/* Make this command interruptable.  */
      read_one_sym (cs, &main_sym, &main_aux);

#ifdef SEM
      temp_sem_val = cs->c_name[0] << 24 | cs->c_name[1] << 16 |
                     cs->c_name[2] << 8 | cs->c_name[3];
      if (int_sem_val == temp_sem_val)
        last_coffsem = (int) strtol (cs->c_name+4, (char **) NULL, 10);
#endif

      if (cs->c_symnum == next_file_symnum && cs->c_sclass != C_FILE)
	{
	  if (last_source_file)
	    coff_end_symtab (objfile);

	  coff_start_symtab ();
	  complete_symtab ("_globals_", 0, first_object_file_end);
	  /* done with all files, everything from here on out is globals */
	}

      /* Special case for file with type declarations only, no text.  */
      if (!last_source_file && SDB_TYPE (cs->c_type)
	  && cs->c_secnum == N_DEBUG)
	complete_symtab (filestring, 0, 0);

      /* Typedefs should not be treated as symbol definitions.  */
      if (ISFCN (cs->c_type) && cs->c_sclass != C_TPDEF)
	{
	  /* record as a minimal symbol.  if we get '.bf' next,
	   * then we undo this step
	   */
	  record_minimal_symbol (cs->c_name, cs->c_value, mst_text);

	  fcn_line_ptr = main_aux.x_sym.x_fcnary.x_fcn.x_lnnoptr;
	  fcn_start_addr = cs->c_value;
	  fcn_cs_saved = *cs;
	  fcn_sym_saved = main_sym;
	  fcn_aux_saved = main_aux;
	  continue;
	}

      switch (cs->c_sclass)
	{
	  case C_EFCN:
	  case C_EXTDEF:
	  case C_ULABEL:
	  case C_USTATIC:
	  case C_LINE:
	  case C_ALIAS:
	  case C_HIDDEN:
	    complain (&bad_sclass_complaint, cs->c_name);
	    break;

	  case C_FILE:
	    /*
	     * c_value field contains symnum of next .file entry in table
	     * or symnum of first global after last .file.
	     */
	    next_file_symnum = cs->c_value;
	    filestring = getfilename (&main_aux);
	    /*
	     * Complete symbol table for last object file
	     * containing debugging information.
	     */
	    if (last_source_file)
	      {
		coff_end_symtab (objfile);
		coff_start_symtab ();
	      }
	    in_source_file = 1;
	    break;

          case C_STAT:
	    if (cs->c_name[0] == '.') {
		    if (strcmp (cs->c_name, ".text") == 0) {
			    /* FIXME:  don't wire in ".text" as section name
				       or symbol name! */
			    if (++num_object_files == 1) {
				    /* last address of startup file */
				    first_object_file_end = cs->c_value +
					    main_aux.x_scn.x_scnlen;
			    }
			    /* Check for in_source_file deals with case of
			       a file with debugging symbols
			       followed by a later file with no symbols.  */
			    if (in_source_file)
			      complete_symtab (filestring, cs->c_value,
					       main_aux.x_scn.x_scnlen);
			    in_source_file = 0;
		    }
		    /* flush rest of '.' symbols */
		    break;
	    }
	    else if (!SDB_TYPE (cs->c_type)
		     && cs->c_name[0] == 'L'
		     && (strncmp (cs->c_name, "LI%", 3) == 0
			 || strncmp (cs->c_name, "LF%", 3) == 0
			 || strncmp (cs->c_name,"LC%",3) == 0
			 || strncmp (cs->c_name,"LP%",3) == 0
			 || strncmp (cs->c_name,"LPB%",4) == 0
			 || strncmp (cs->c_name,"LBB%",4) == 0
			 || strncmp (cs->c_name,"LBE%",4) == 0
			 || strncmp (cs->c_name,"LPBX%",5) == 0))
	      /* At least on a 3b1, gcc generates swbeg and string labels
		 that look like this.  Ignore them.  */
	      break;
	    /* fall in for static symbols that don't start with '.' */
	  case C_EXT:
	    if (!SDB_TYPE (cs->c_type)) {
		/* FIXME: This is BOGUS Will Robinson! 
	 	Coff should provide the SEC_CODE flag for executable sections,
	 	then if we could look up sections by section number we
  	 	could see if the flags indicate SEC_CODE.  If so, then
	 	record this symbol as a function in the minimal symbol table.
		But why are absolute syms recorded as functions, anyway?  */
		    if (cs->c_secnum <= text_bfd_scnum+1) {/* text or abs */
			    record_minimal_symbol (cs->c_name, cs->c_value,
						   mst_text);
			    break;
		    } else {
			    record_minimal_symbol (cs->c_name, cs->c_value,
						   mst_data);
			    break;
		    }
	    }
	    process_coff_symbol (cs, &main_aux, objfile);
	    break;

	  case C_FCN:
	    if (strcmp (cs->c_name, ".bf") == 0)
	      {
		within_function = 1;

		/* value contains address of first non-init type code */
		/* main_aux.x_sym.x_misc.x_lnsz.x_lnno
			    contains line number of '{' } */
		if (cs->c_naux != 1)
		  complain (&bf_no_aux_complaint, (char *) cs->c_symnum);
		fcn_first_line = main_aux.x_sym.x_misc.x_lnsz.x_lnno;

		new = (struct coff_context_stack *)
		  xmalloc (sizeof (struct coff_context_stack));
		new->depth = depth = 0;
		new->next = 0;
		coff_context_stack = new;
		new->locals = 0;
		new->old_blocks = pending_blocks;
		new->start_addr = fcn_start_addr;
		fcn_cs_saved.c_name = getsymname (&fcn_sym_saved);
		new->name = process_coff_symbol (&fcn_cs_saved,
						 &fcn_aux_saved, objfile);
	      }
	    else if (strcmp (cs->c_name, ".ef") == 0)
	      {
		      /* the value of .ef is the address of epilogue code;
		       * not useful for gdb
		       */
		/* { main_aux.x_sym.x_misc.x_lnsz.x_lnno
			    contains number of lines to '}' */
		new = coff_context_stack;
		if (new == 0)
		  {
		    complain (&ef_complaint, (char *) cs->c_symnum);
		    within_function = 0;
		    break;
		  }
		if (cs->c_naux != 1) {
		  complain (&ef_no_aux_complaint, (char *) cs->c_symnum);
		  fcn_last_line = 0x7FFFFFFF;
		} else {
		  fcn_last_line = main_aux.x_sym.x_misc.x_lnsz.x_lnno;
		}
		enter_linenos (fcn_line_ptr, fcn_first_line, fcn_last_line);

		coff_finish_block (new->name, &coff_local_symbols, new->old_blocks,
			      new->start_addr,
#if defined (FUNCTION_EPILOGUE_SIZE)
			      /* This macro should be defined only on
				 machines where the
				 fcn_aux_saved.x_sym.x_misc.x_fsize
				 field is always zero.
				 So use the .bf record information that
				 points to the epilogue and add the size
				 of the epilogue.  */
			      cs->c_value + FUNCTION_EPILOGUE_SIZE,
#else
			      fcn_cs_saved.c_value +
			          fcn_aux_saved.x_sym.x_misc.x_fsize,
#endif
			      objfile
			      );
		coff_context_stack = 0;
		within_function = 0;
		free ((PTR)new);
	      }
	    break;

	  case C_BLOCK:
	    if (strcmp (cs->c_name, ".bb") == 0)
	      {
		new = (struct coff_context_stack *)
			    xmalloc (sizeof (struct coff_context_stack));
		depth++;
		new->depth = depth;
		new->next = coff_context_stack;
		coff_context_stack = new;
		new->locals = coff_local_symbols;
		new->old_blocks = pending_blocks;
		new->start_addr = cs->c_value;
		new->name = 0;
		coff_local_symbols = 0;
	      }
	    else if (strcmp (cs->c_name, ".eb") == 0)
	      {
		new = coff_context_stack;
		if (new == 0 || depth != new->depth)
		  error ("Invalid symbol data: .bb/.eb symbol mismatch at symbol %d.",
			 symnum);
		if (coff_local_symbols && coff_context_stack->next)
		  {
		    /* Make a block for the local symbols within.  */
		    coff_finish_block (0, &coff_local_symbols, new->old_blocks,
				  new->start_addr, cs->c_value, objfile);
		  }
		depth--;
		coff_local_symbols = new->locals;
		coff_context_stack = new->next;
		free ((PTR)new);
	      }
	    break;

	  default:
	    process_coff_symbol (cs, &main_aux, objfile);
	    break;
	}
    }

  if (last_source_file)
    coff_end_symtab (objfile);
  fclose (stream);

  /* Patch up any opaque types (references to types that are not defined
     in the file where they are referenced, e.g. "struct foo *bar").  */
  ALL_OBJFILE_SYMTABS (objfile, s)
    patch_opaque_types (s);

  discard_cleanups (old_chain);
  current_objfile = NULL;
}

/* Routines for reading headers and symbols from executable.  */

#ifdef FIXME
/* Move these XXXMAGIC symbol defns into BFD!  */

/* Read COFF file header, check magic number,
   and return number of symbols. */
read_file_hdr (chan, file_hdr)
    int chan;
    FILHDR *file_hdr;
{
  lseek (chan, 0L, 0);
  if (myread (chan, (char *)file_hdr, FILHSZ) < 0)
    return -1;

  switch (file_hdr->f_magic)
    {
#ifdef MC68MAGIC
    case MC68MAGIC:
#endif
#ifdef NS32GMAGIC
      case NS32GMAGIC:
      case NS32SMAGIC:
#endif
#ifdef I386MAGIC
    case I386MAGIC:
#endif
#ifdef CLIPPERMAGIC
    case CLIPPERMAGIC:
#endif
#if defined (MC68KWRMAGIC) \
  && (!defined (MC68MAGIC) || MC68KWRMAGIC != MC68MAGIC)
    case MC68KWRMAGIC:
#endif
#ifdef MC68KROMAGIC
    case MC68KROMAGIC:
    case MC68KPGMAGIC:
#endif
#ifdef MC88DGMAGIC
    case MC88DGMAGIC:
#endif      
#ifdef MC88MAGIC
    case MC88MAGIC:
#endif      
#ifdef I960ROMAGIC
    case I960ROMAGIC:		/* Intel 960 */
#endif
#ifdef I960RWMAGIC
    case I960RWMAGIC:		/* Intel 960 */
#endif
	return file_hdr->f_nsyms;

      default:
#ifdef BADMAG
	if (BADMAG(file_hdr))
	  return -1;
	else
	  return file_hdr->f_nsyms;
#else
	return -1;
#endif
    }
}
#endif

/* Read the next symbol, swap it, and return it in both internal_syment
   form, and coff_symbol form.  Also return its first auxent, if any,
   in internal_auxent form, and skip any other auxents.  */

static void
read_one_sym (cs, sym, aux)
    register struct coff_symbol *cs;
    register struct internal_syment *sym;
    register union internal_auxent *aux;
{
  int i;

  cs->c_symnum = symnum;
  fread (temp_sym, local_symesz, 1, nlist_stream_global);
  bfd_coff_swap_sym_in (symfile_bfd, temp_sym, (char *)sym);
  cs->c_naux = sym->n_numaux & 0xff;
  if (cs->c_naux >= 1)
    {
    fread (temp_aux, local_auxesz, 1, nlist_stream_global);
    bfd_coff_swap_aux_in (symfile_bfd, temp_aux, sym->n_type, sym->n_sclass,
			  (char *)aux);
    /* If more than one aux entry, read past it (only the first aux
       is important). */
    for (i = 1; i < cs->c_naux; i++)
      fread (temp_aux, local_auxesz, 1, nlist_stream_global);
    }
  cs->c_name = getsymname (sym);
  cs->c_value = sym->n_value;
  cs->c_sclass = (sym->n_sclass & 0xff);
  cs->c_secnum = sym->n_scnum;
  cs->c_type = (unsigned) sym->n_type;
  if (!SDB_TYPE (cs->c_type))
    cs->c_type = 0;

  symnum += 1 + cs->c_naux;
}

/* Support for string table handling */

static char *stringtab = NULL;

static int
init_stringtab (chan, offset)
    int chan;
    long offset;
{
  long length;
  int val;
  unsigned char lengthbuf[4];

  if (stringtab)
    {
      free (stringtab);
      stringtab = NULL;
    }

  if (lseek (chan, offset, 0) < 0)
    return -1;

  val = myread (chan, (char *)lengthbuf, sizeof lengthbuf);
  length = bfd_h_get_32 (symfile_bfd, lengthbuf);